Motor-pump apparatus



Aug. 22, 1961 e. w. WRIGHT MOTOR-PUMP APPARATUS Original Filed June 9,1955 Fug 1 Fig. 3

T w .m%. 2 mww m 1 m 7 F2 NW R O E GM United States Patent p 2,996,994MOTOR- PUMP APPARATUS George W. Wright, Fort Wayne, Ind., assignor toTokheim Corporation, Fort Wayne, Ind, a corporation of Indiana Originalapplication June 9, 1955, Ser. No. 514,221. Divided and this applicationMay 4, 1959, Ser. No.

6 Claims. (Cl. 103-87) This invention relates to apparatus for pumpingliquid fuel, especially for automotive use, and particularly to asubmersible motor-pump unit comprising a centrifugal fuel pump and anenclosed motor coupled by a magnetic coupling operating through animperforate wall of the motor housing, as more broadly disclosed andclaimed in the copending application of William L. Hudson, Serial No.538,753, filed October 15, 1955, now Patent No. 2,885,126. Thisapplication is a division of my copending application Serial No.514,221, filed June 9, 1955.

It is an object of the invention to provide a pump unit for submergedoperation in a body of liquid fuel such as the gasoline in a fuel tank,especially an automotive fuel tank; and more particularly to provide animproved motor and pump assembly in which the form and interrelation ofparts is adapted to facilitate commercial production. :It is a furtherobject of the invention to provide such a fuel pump unit which iscompact and adapted to fit a variety of fuel tanks, including theshallow tanks commonly used in passenger cars and the tall narrow tankscommonly used in trucks; which will be highly reliable in operation andhave a long life and require a minimum of service; and which will havesuch reliability under the adverse mounting and operating conditions ofan automotive vehicle.

It is an especial object of the invention to provide a combinedfuel-pump and motor unit adapted for mass production at relatively lowcost.

Further andmore specific objects of the invention will appear from thefollowing specification.

In accordance with one aspect of the invention, the motor of themotor-pump apparatus is formed as a selfcontained and permanentlyenclosed and sealed unit, containing the driving member of the magneticcoupling; and a pump and driven member of the coupling are subsequentlyassembled to such motor unit and mechanically secured thereto.

In accordance with another aspect of the invention, the motor-pumpassembly comprises a tubular housing, preferably in the form of acylindrical tube, and such tube serves as alining and guiding means forand between the motor and the pump and the coupling parts, to positionthem in assembled and operating relationship. The motor is alined andguided in the tube, preferably with its shaft co-axial with the tube,and the tube forms the main outer wall of the housing in which the motoris sealed. The lower end wall of the housing is formed by a nonmagneticimperforate wall inserted and sealingly fixed in the tube at a pointintermediate its length to provide a downwardly projecting cylindricalskirt accurately positioned in relation to the motor shaft and adaptedto aline and guide the pump. The driving and driven members of themagnetic coupling lie on opposite sides of the imperforate wall, whichserves as a rigid sealing diaphragm between them. Preferably the motorand especially its shaft and the driving member of the coupling areaxially positioned by and in reference to the said im perforate wall.The top end of the motor housing is closed by a cap or other closuremember sealingly fixed in place, and such closure member desirablyserves as a retaining member to secure the motor in fixed relation tothe imperforate wall.

2,996,994 Patented Aug. 22, 1961 The accompanying drawings illustratethe invention. In such drawings:

FIG. 1 is a vertical section of a pump-motor unit embodying theinvention, associated with a bottom mounts;

FIG. 2 is a bottom plan view of the pump-motor unit and mounting shownin FIG. 1;

FIG. 3 is a vertical section taken generally on the line 33 of FIG. 1and more specifically on the line 3-3 of FIG. 4, and showing a mountingclip on an enlarged scale; and

FIG. 4 is a section taken on the line 4-4 of FIG. 3.

The assembly shown in the drawing is adapted for quantity production asa substantially permanently as sembled unit. The main body of thepump-motor unit comprises a tubular shell 200, conveniently made ofcommercial tubing. An imperforate wall or diaphragm 262 is inserted inits lower end, and is fixed and sealed in place as by soldering. Thecenter of the diaphragm 202 carries a thrust bearing insert 204 and adepending sleeve hearing 206, which are secured and sealed to thediaphragm as by welding or soldering. Above the diaphragm 202, and shell200 receives a motor-supporting spacer 208 which may be molded from asynthetic resin material such as nylon and is generally cylindrical inshape. ilt rests on the diaphragm, and its upper portion fits closelywithin the shell 20%. At three spaced points around its upper edge, itis provided with upward extensions 289 to center the motor 216 withinthe shell 200.

The motor assembly 210 is inserted within the shell 2% to rest on theupper face of the spacer 268. It is held down, and its upper end iscentered, by a stabilizing plate 212 molded of synthetic resin such asnylon. The stabilizing plate is held in place, and the upper end of theshell 209 is closed, by a cap 214 which has a central tubular upwardextension 216. This receives a grommet 218 through which the motor leadsare passed. Such leads include a live lead 219 and a ground lead 229,the latter being connected to one of the bolts 222 which hold the motorassembly 21% together. The tubular extension 216 of the cap 214 isconnected and sealed to a conduit 224 which carries the motor leads andserves to stabilize the mounting described below. The conduit isdesirably sealed, as with a mass of sealing com pound 225.

The motor shaft 226 is carried by radial and thrust bearings in themotor 210 and its lower end projects downwardly and is provided with adrive pin 228. The driving member 230 of a magnetic coupling is slidablyand drivingly mounted on the end of the shaft 226, and carries anannular magnet 232. The magnet is conveniently a pressed ferrite magnet,magnetized after assembly in its carrier 230 to provide fourcircumferentially spaced poles at its lower face. The member 230 may bean anodized aluminum casting provided at its center with a hardenedcup-shaped thrust bearing insert 234 which rides on a thrust ballbetween itself and the diaphragm insert 204.

The shell 20%) projects a short distance below the diaphragm 2il2, andslidably receives a pump body casting 240 to guide and aline the samewith respect to the motor 21d and the magnetic driving member 230. Suchcasting forms the upper wall 242 of the pump casing, and has a rim M4which lies in proximate relation to the lower edge of the shell 200.Three circumferentially spaced posts 246 extend upward from the pumpbody 2 40 and fit closely within the lower end of the shell 2'00. Theirupper ends abut the lower face of the diaphragm 202, and support ashroud 248 which forms a housing for the driven member 250 of themagnetic coupling.

The pump body 240 is conveniently secured in place 3 by one or more pins252 pressed into alined holes in the shell 200 and the legs 246.

The lower end of the shell 200, between the posts 246, is punched toprovide inlet openings 254, and these are covered by a screen 256wrapped around the lower end of the shell 200 and overlapping the rim244 of the body 240.

The lower half of the pump casing is formed by a cover 260, whichprovides the lower wall 262 of the pump housing. A volute 264 is formedby the pump body and cover, around the pump chamber, and leads to asocket in the pump body 240 which receives the lower end of thedischarge pipe 266.

The bottom throat of the pump is formed in the bottom pump casing Wall262, and is bridged by a spider 272 which supports a bearing sleeve 274for the lower end of the pump shaft 276. The bearing sleeve may beintegral and homogeneous with the cover 260 when that cover is made of abearing material. The bottom throat is protected by a screen 270 fittedwithin a tapering collar 268 on the body 260 and held in place by a snapring 269.

The pump shaft 276 is journaled at its ends in the sleeve bearing 206 onthe diaphragm and in the bearing sleeve 274 of the pump cover. Its upperend face forms a thrust bearing riding against a thrust ball receivedbetween it and the diaphragm insert 204.

The driven member 250 of the magnetic coupling is similar inconstruction to the driver member 230, and carries a companion magnet251 magnetized after assembly in its carrier to provide magnetic polesat its upper face in positions for alinement with the poles of thedriving magnet 231. The driven member 250 is fixed on the upper end ofthe pump shaft 276, as by a press fit on a knurled section of the shaft,and the magnetic traction holds the shaft upward against the thrustbearing and fixes its axial position. The shroud 248 encloses the drivenmember 250 to prevent agitation and stirring of the liquid in the tankby the rota tion of that member 250.

The pump impeller has a central hub which is pressed on a knurledsection of the pump shaft 276, and has a ctrcular central web of smoothand uninterrupted surface configuration Within the throats of the pump,and such web supports spaced impeller blades which revolve in the pumpchamber defined by the walls 242 and 262.

The pump body 240 and cover 260 are provided with peripheral flanges 241and 261 and are secured together by four rivets 280 passed through suchflanges at spaced points around the periphery of the pump. The flangesmay be used as a mounting for the pump and motor assembly.

In the mounting shown, the pump-motor unit is carried by its flanges 241and 261 on a bracket 300 secured to the bottom wall of a tank 52. Thebracket has a raised mounting plate 302, with downwardly oflset feet atits end edges which support the plate above the bottom of the tank. Thepump flanges 241 and 261 are of unsymmetrical peripheral shape, andmounting plate 302 is punched to provide an opening of generally similarunsymmetrical shape. To orient the pump with respect to the bracket 300,the plate 302 carries four upturned guide posts 304, and the flanges ofthe pump are provided withflat outer faces in complementary relationshipwith the inner faces of those posts 304. The relationship permits thepump to be inserted in only a single position, and the posts 304 looselyreceive and guide the pump housing as it is inserted.

The pump is secured in place on the bracket by snap fasteners,comprising clips carried by either the pump and bracket and engaged withretainers carried by the other. As shown, the assembled flanges 241 and261 are provided with three circumferentially spaced rectangularopenings 306, with that portion of each opening which lies in the flange2'41 being slightly wider than the portion which lies in the cover 260.A generally U-shaped spring clip 308 is inserted upwardly in each of theopenings 306. At the outer side of the central plane of each clip, itsside walls are deformed outward to form clip-retaining fingers or lugs310 which engage over the upper edges of the pump body flange 261 toretain the clip in its opening 306. At the inner side of the centralplane of each clip 30%, its side walls are deformed inward to formspring latches 312. For cooperation with the three clips 308, thebracket plate 3 0?. carries three upturned retaining fingers 314 whichhave notches 316 in their side edges, as shown in FIG. 3, to receive thespring latches 312. The guide posts 304 orient the pump in properrelationship with the bracket, and aline the clips 308 with theretaining fingers 314, and when the pump is then pressed downward to itsmounting position, the spring latches 312 engage over the retainingfingers 314 and in the notches 316 to secure the pump assembly on themounting bracket 300.

The top wall of the fuel tank 52 is provided with a suitable opening forinsertion of the pump-motor assembly, and such opening is closed by acover plate 320. Such cover plate has a central opening containing anelastic grommet 322 to closely embrace the upper end of r the conduit224 at the top of the motor and pump assembly. The upper end of thegrommet 322 is closed by a terminal shield 324 through which the leads219 and 220 are passed. The plate 320 also carries a pump dischargefitting 326, in communication with a depending socket 328 which receivesthe upper end of the pump discharge pipe 266. The upper end of such pipedesirably carries an elastic grommet 330 which frictionally engages thewall of the socket 328.

In mounting the pump, the pump-motor assembly, in-

eluding a discharge pipe 266 carried in the socket of the pump body, isinserted through the opening in the tank top wall, is properly orientedwith respect to the bracket 300 by engagement of the flanges 241 and 261between the posts 304, and is then pressed firmly downward to engage theretaining posts 314 in the clips 308 carried in the openings 306 of thepump flanges. The cover plate 320 is then applied to the top tank wall.motor leads 219 and 220 are led up through the grommet 322, and thatgrommet is then engaged over the end of the conduit 224, and the socket328 is engaged over the tion, as noted above, for its engagement in thegrommet 322 stabilizes the upper end of the assembly, to suppressvibnation and prevent rocking movements which might tend to dislodge thepump from its mounting bracket 300. The grommets 322 and 330 preventtransmission of vibration to the top wall of the tank.

The conduit 224 and discharge pipe 266 can be made of any desired lengthto suit the depth of the tank in which the assembly is mounted. Thus, ina shallow passhown in FIG. 1; while in a tall tank such as is commonlyIn the motor-pump unit shown, the motor 210 and the driving member 230of the coupling are completely enclosed in the compartment formed abovethe imperforate wall or diaphragm 202, and such compartment ispermanently and hermetically sealed, particularly from the tank. Whilethe compartment might be permitted to breathe to the atmosphere outsidethe tank, by providing for leakage past the grommet 218 in the conduit224 and along the wire leads 219 and 220 Where they pass through theterminal shield, I prefer that the assembly be permanently sealed. Insuch care, the motor compartment may be filled with a controlledatmosphere favorable to motor operation and life.

Operation of the motor rotates the driver 230 of the magnetic coupling,and the driven member 250, being magnetically coupled thereto, is drivenat the same speed. The torque required for nornral operation of thesmall centrifugal pump is readily transmitted by the coupling, and thecoupling effect is desiraibly limited to a value sufficient for normalpump operation but less than the normal torque of the motor and lessthan sufficient to reestablish itself during operation once it isbroken. If the pump should become locked, the coupling effect would thenbe broken and the motor would run free, without danger of overheating orburning out.

I claim as my invention:

1. A motor-pump unit adapted for submerged operation in a body of liquidsuch as gasoline, comprising a cylindrical tube, an imperforate wallsealingly fixed in said tube intermediate the length thereof, a motorassembly having a shaft and bearings supporting the same, motor-supportmeans centered and guided in said tube and located axially therein byengagement with said imperforate wall, said means supporting said motorassembly in the tube in predetermined relation to one side of said wallwith its shaft substantially coaxial with said tube, a cover closing themotor-containing end of the tube for enclosing the motor assembly in thetube between said Wall and cover, means coacting with said cover toretain said motor assembly in supported relation with said motorsupport, a pump having a shaft and a housing, pumplocating means on saidhousing disposed substantially coaxially with said pump shaft andreceived in and guided by said tube for supporting said pump with itsshaft substantially coaxial with said tube at the opposite side of saidwall from said motor shaft and substantially coaxial with said motorshaft, said pump-locating means coacting with said imperforate wall toposition said pump in predetermined relation axially of said tube, meansfor holding said pump housing in assembled relation with said tube, andmagnetic coupling means including driving and driven members operativelyconnected to said motor and pump shafts. respectively on opposite sidesof said imperforate wall and magnetically coupled therethro ugh foroperatively connecting said shafts.

2. A motor-pump unit according to claim 1, with the addition of thrustbearing means between said imperforate wall and each of said motor shaftand said pump shaft to fix said shafts axially with respect to eachother and to said motor assembly and pump housing.

3. A motor-pump unit according to claim 1, including means engaging andguided by said tube for positioning the upper end of said motor in saidtube, said means being retained in motor-positioning relation by saidcover.

4. A motor-pump unit according to claim 1, including a tubular motorsupport received in said tube and engaged against said imperforate wall,said support serving to space the motor from the wall to define a chambetherebetween for housing said driving means. i

5. A motor-pump unit adapted for submerged operation in a body of liquidsuch as gasoline, comprising a cylindrical tube, an imperforate Wallsealed in said tube adjacent its lower end, a motor assembly having ashaft and bearings supporting the same, means cooperating With said tubeas a guide for supporting said motor assembly in the tube with its shaftsubstantially coaxial with the tube, a cover enclosing the motor in thetube beween said wall and said cover, a pump having a shaft and ahousing, means cooperating with said tube as a guide for supporting saidpump in and substantially proximate to the end of the tube with theshaft of the pump substantially coaxial with the tube and with the motorshaft on the opposite side of said wall from the motor shaft, andmagnetic coupling means on opposite sides of said wall and operativelyconnecting said motor and pump shafts, said pump housing defining a topinlet throat facing said imperforate wall, said tube having a relativelylarge opening therein below said imperforate wall for establishingcommunication between said throat and the space surrounding themotor-pump unit to admit liquid thereto from a body of liquid in whichthe unit is mounted.

6. A motor-pump unit according to claim 5, which includes means forsupporting said tube substantially vertically in the body of liquid, andwherein said pump re leases gas upward through said throat, said openingin the tube extending substantially to said diaphragm so that gasdischarged from said throat may escape from said tube above the level ofliquid flowing to said throat through the opening.

References Cited in the file of this patent UNITED STATES PATENTS2,230,717 Lancey Feb. 4, 1941 2,370,590 Taylor Feb. 27, 1945 2,463,409Moody Mar. 1, 1949 2,729,962 Hicklin Jan. 10, 1956

